Daily grind: Fossil molars add to Neanderthal debate

Nov 22, 2006

Three-dimensional virtual reconstruction of the deciduous and permanent Neanderthal molars. Both enamel and dentin are rendered in transparency to show the pulp chamber and the root canals. Credit: Luca Bondiolli and Arnaud Mazurier

Palaeontologists have fired a new round in a verbal battle over the Neanderthals, the hominids who were our closest evolutionary cousins before they met a strange and possibly tragic end.

Scientists from the United Kingdom, France and Italy have studied teeth from Neanderthals with X-rays from the European Synchrotron Radiation Facility. They found that the dental development of Neanderthals is very similar to modern humans.

Neanderthals first appeared in Europe approximately 200,000 years ago and became extinct about 25,000 years ago. These predecessors of modern humans have always been considered genetically closer to us than any other members of the genus Homo. It has even been suggested that Neanderthals achieved adulthood faster than modern humans do today.

A research team from the United Kingdom, France and Italy has recently shed new light on this theory by studying this species’ teeth. Teeth express genetic differences found between individuals and different populations more efficiently than any other tissues preserved in the fossil record. Studies with teeth can identify a timescale on the entire period of dental development that occurs from before birth until adulthood.

Scientists used the ESRF X-rays to study the enamel dentine junction of a deciduous and a permanent Neanderthal molar tooth (approximately 130,000 years old) that was found on a site in France. The technique used to image the teeth is high-resolution tomography. The researchers noticed that the samples showed more complex folding of the enamel dentine junction than their modern human counterparts. Some of the unique surface morphologies of Neanderthal molars clearly showed a deep embryological origin and are likely to have been functionally significant.

Thin ground sections of the same Neanderthal molars revealed that the crowns and roots did not grow faster than those of modern humans. The permanent molar tooth studied had completed its root growth at about 8.7 years of age, which is typical of many modern human children today.

Almost all deciduous teeth contained an accentuated birth line, or neonatal line that results from the changing physiology and stress of birth. The Neanderthal deciduous also showed a neonatal line with evidence of the usual perinatal physiological stress but with no signs of additional postnatal stress.

Among anthropoid primates there is a close relationship between brain growth and tooth eruption. Scientists predicted that the first permanent molar eruption in this Neanderthal (6.8 years) fits a dental development schedule similar to those found in modern humans.

The next step in the research is to find out whether Neanderthal teeth from sites dated to more recent times will reveal evidence of the demographic pressures that overcame the Neanderthals as they approached extinction.

Relevant PhysicsForums posts

Related Stories

Neanderthal communities divided some of their tasks according to their sex. This is one of the main conclusions reached by a study performed by the Spanish National Research Council (CSIC), published in the ...

Until a few months ago, many scientific articles, including those published in 'Nature', dated the disappearance of the Neanderthals (Homo neanderthalensis) from Europe at around 40,000 years ago. However, a new study sho ...

Members of our species (Homo sapiens) arrived in Europe several millennia earlier than previously thought. At this conclusion a team of researchers, led by the Department of Anthropology, University of Vie ...

A sophisticated new examination of teeth from 11 Neanderthal and early human fossils shows that modern humans are slower than our ancestors to reach full maturity. The finding suggests that our characteristically ...

Columbus, Ohio, researchers say they've determined Neanderthal tooth development was similar to that of modern humans. The Ohio State University researchers said their findings suggest the maturation period of the two hominid ...

Recommended for you

UCLA life scientists have created an accurate new method to identify genetic markers for many diseases—a significant step toward a new era of personalized medicine, tailored to each person's DNA and RNA.

While studying a ground-nesting bird population near El Reno, Okla., a University of Oklahoma-led research team found that stress during a severe weather outbreak of May 31, 2013, had manifested itself into malformations ...

(Phys.org)—There is no mistaking the first action potential you ever fired. It was the one that blocked all the other sperm from stealing your egg. After that, your spikes only got more interesting. Waves ...

The robust advances in pain management for companion animals underlie the decision of the American Animal Hospital Association (AAHA) and the American Association of Feline Practitioners (AAFP) to expand on the information ...

(Phys.org)—A pair of researchers with Harvard University has uncovered one of the secrets behind pigeons' impressive flight abilities. In their paper published in Proceedings of the National Academy of ...

User comments : 0

Please sign in to add a comment.
Registration is free, and takes less than a minute.
Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.

Javascript is currently disabled in your web browser. For full site functionality, it is necessary to enable Javascript.
In order to enable it, please see these instructions.